In the past, as shown in FIG. 4, there have been proposed an electricity feeding control device 100, which controls power feeding from an external power source (not shown) to an electrical automobile (not shown) comprising a battery (not shown) and a charge circuit (not shown) for charging the battery (for example, see Japanese Patent Application Laid-Open No. 2009-234392). Then, this electricity feeding control device 100 comprises a relay 110, a residual current transformer ZCT, and a control circuit 112. The relay 110 is inserted into, respectively, a first power feeding line L1 and a second power feeding line L2, which constitute a part of a power feeding channel leading from the external power source to the charge circuit, and opens and closes the first and second power feeding lines L1, L2. The residual current transformer ZCT is located between the relay 110 and the below-described power side plug PP, and is penetrated by the first and second power feeding lines L1, L2. The control circuit 112 switches off the relay 110, when detecting a leakage based on an output (that is, unbalance current) of the residual current transformer ZCT.
The electricity feeding control device 100, having a configuration shown in FIG. 4, comprises a power side plug PP connected to the external power source via a first cable C1 (see FIG. 5), and a car side plug CP connected to the electrical automobile via a second cable C2 (see FIG. 5). Then, the power side plug PP is electrically connected to the car side plug CP through the first and second power feeding lines L1, L2. In addition, the electricity feeding control device 100, having a configuration shown in FIG. 4, comprises a power circuit 111 for supplying power to the control circuit 112. The power side plug PP and the car side plug CP are provided with ground terminals (not shown) which are grounded, respectively, and these ground terminals are connected each other through a grounding wire L3. By the way, the charge circuit of the electrical automobile generates a relay control signal for causing the control circuit 112 to switch on/off the relay 110. Then, the relay control signal is inputted to the car side plug CP in the electricity feeding control device 100 through the second cable C2. In the electricity feeding control device 100, by contrast, the car side plug CP and the control circuit 112 are connected each other through a signal line L4, and the relay control signal, inputted to the car side plug CP, is transmitted to the control circuit 112 through the signal line L4.
In this electricity feeding control device 100, as shown in FIG. 5, a first base plate 121 in which the power circuit 111 is formed, a second base plate 122 in which the control circuit 112 is formed, and the relay 110 are attached to a supporting member 104, and are housed within a box-shaped housing case 103.
The housing case 103 comprises a body 131 which is formed into a box-shape of about a rectangular parallelepiped and of which one face is opened, and a cover 132 which is formed into a box-shape of about a rectangular parallelepiped and of which one face is opened. Then, the cover 132 is attached to the opened one face of the body 131 with attachment screws S1.
By the way, this kind of electricity feeding control device is mainly used out of doors. Therefore, the housing case 103 is cooled during nighttime or winter-time in which the air temperature drops, and thus there is a possibility that a dew condensation is generated within the housing case 103.
By contrast, as shown in FIG. 6, there have been proposed an electricity feeding control device, of which the body 131 is provided in its internal wall with a straight-tube-shaped rib 131d. Then, the rib 131d is penetrated through its inside from its distal end to an outer surface of the housing case 103, and to form thereby an air hole 131c through which an air can pass between the inside and outside of the housing case 103. Also, an inner pressure adjusting sheet 105, which comprises a porous sheet etc. having breathability and waterproof property, is arranged so as to cover the air hole 131c from the inside of the housing case 103, in order to prevent a foreign matter and a water (a water drop) from getting into the inside of the housing case 103 through the air hole 131c. Herein, if the temperature in the inside of the housing case 103 is higher than that in the outside of the housing case 103, an inner pressure of the housing case 103 increases, and an air in the inside of the housing case 103 flows out to the outside of the housing case 103 through the inner pressure adjusting sheet 105 and the air hole 131c. By contrast, if the temperature in the inside of the housing case 103 is lower than that in the outside of the housing case 103, the inner pressure of the housing case 103 decreases, and an air in the outside of the housing case 103 flows into the inside of the housing case 103 through the air hole 131c and the inner pressure adjusting sheet 105. Thus, air ventilation is performed between the inside and outside of the housing case 103, and thereby can eliminate almost a temperature difference from the outside and the inside of the housing case 103. Therefore, the above electricity feeding control device can prevent the dew condensation from being generated within the housing case 103.
However, in the electricity feeding control device 100 having the configuration shown in FIG. 6, the air hole 131c is formed into a straight-tube-shape, and thus an incident ultraviolet light from the outside of the housing case 103 is directly illuminated to the inner pressure adjusting sheet 105. As a result, there is a possibility that the inner pressure adjusting sheet 105 deteriorates due to the incidence of the ultraviolet light.
In addition, if an elongated rod (for example, a driver etc.) is accidentally inserted into the air hole 131c from the outside of the housing case 103, upon maintenance etc., there is a possibility that the inner pressure adjusting sheet 105 is damaged by the contact of a distal end of the rod with the inner pressure adjusting sheet 105.